Statistical analysis revealed no significant differences in IDO1 expression based on the patient's clinical data, including gender, age, tumor location, allergy history, hypertension history, cardiovascular disease history, tumor history, diabetes (both type 1 and type 2), body mass index, smoking history, family history, alcohol history, and tumor maximum diameter (<i>P</i> > 0.05). This evidence concerns the gene IDO1 and diabetes mellitus.